<template>
  <div>
      <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
          <div class="iconfont header-abs-back">&#xe624</div>
      </router-link>
      <div class="header-fixed" :style="opacityStyle" v-show="!showAbs">
        <router-link tag="div" to="/">
            <div class="iconfont header-fixed-back">&#xe624</div>
        </router-link>
          景点详情
      </div>
  </div>
</template>

<script>
export default {
    data(){
        return{
            showAbs:true,
            opacityStyle:{
                opacity:0
            }
        }
    },
    methods:{
        handleScroll(){
            console.log("判断滚动");
            const top=document.documentElement.scrollTop
            if(top>60 &&top<140){
                const opacity=(top/140)
                this.opacityStyle.opacity=opacity
                this.showAbs=false
            }else if(top>60){
                this.showAbs=false
            }
            else{
                this.showAbs=true
            }
        }
    },
    activated(){
        window.addEventListener('scroll',this.handleScroll)
    },
    deactivated(){
        window.removeEventListener('scroll',this.handleScroll)
    }
}
</script>

<style lang="stylus" scoped>
@import "~@/assets/styles/varibles.styl"
.header-abs
    position absolute
    left .2rem
    top .2rem
    width .8rem
    height .8rem
    line-height .8rem
    text-align center
    border-radius .4rem
    background rgba(0,0,0,.8)
    .header-abs-back
        color #fff
        font-size .4rem
.header-fixed
    z-index 2
    position fixed
    top 0
    left 0
    right 0
    height $headerHeight
    height .86rem
    line-height .86rem
    text-align center
    overflow hidden
    color #fff
    background $bgColor
    font-size .32rem
    .header-fixed-back
        position absolute
        color #fff
        top 0
        left 0 
        width .64rem
        text-align center
        font-size .4rem
</style>